1. Field of the Invention
The present invention relates to an alarm system and an alarm method for a vehicle, and more particularly, to an alarm system and an alarm method capable of detecting vehicle speed, simultaneously determining movement statuses of a plurality of targets, and accordingly controlling alarms.
2. Description of the Prior Art
According to the statistics, most of traffic accidents are related to drivers' distraction. If a driver is alerted at 0.5 seconds before being likely to have a collision, it can avoid at least 60% of rear-end collisions, 30% of head-on collisions and 50% of road ramp related traffic accidents. If alerted before 1 second, it can avoid 90% of traffic accidents. The statistics shows traffic accidents can be effectively reduced if the drives have enough reaction time. Vehicle alarm systems, e.g., a blind spot detection (BSD) system, a forward/rear collision warning system, are smart vehicle equipments developed for such needs. However, the vehicle alarm systems in the prior art have higher installation complexity, and adverse to aftermarket of vehicles, such that most equipments may not be applied to vehicles after leaving factories.
Take the BSD system as an example, the BSD system is a safety protection technique for vehicles, and utilizes a radar sensing technique of millimeter wave to achieve early warning. More specifically, the BSD system uses an image self-recognition method of machine vision, to detect obstacles in blind spot areas on left/right/front sides of a vehicle. If the BSD system detects that a specific obstacle exists in a blind spot area, the BSD system actively sends out a message of light or sound, for example, to a driver, so that the driver may change a driving direction accordingly, to avoid a traffic accident due to the driver's careless or blind side of vision.
Generally speaking, the BSD system deploys sensors in rear and/or front bumpers of a vehicle, emits millimeter wave radio signals, and receives corresponding reflecting signals, to determine whether there is an obstacle, such as another vehicle or a person, within a specific range. Additionally, in order to differentiate moving statuses of detecting targets to avoid erroneous determination or alarming, the BSD system requires vehicle related information such as velocity and angle deviation of the vehicle, to determine whether to start BSD or perform debugging. However, the vehicle related information is acquired from an electric control unit of the vehicle through a transmission line or wire. Under such a condition, connection of wires in the vehicle become more complex, especially for a modern smart vehicle, which is equipped with more and more functions and accessories (e.g., lane departure warning radar, reversing radar, anti-lock brake system, electric stable control system). Meanwhile, data robust is required during transmission, to avoid interferences from vehicle electric elements or environment noise. For example, ignition system, battery, wipers, electric windows, electric seats, air conditioner, radio, fuel supply system, clutch system, etc. can generate noise; or high-voltage, temperature/humidity changes of external environment may affect stability or accuracy of data transmission.
Moreover, data output from a vehicle electric control unit may not match a data specification of the BSD system, and it needs to transform the transmission data again, therefore delaying the data operation needed for real-time synchronization and causing time delays. Furthermore, if the BSD system targets for the aftermarket, meaning that the suppliers have no chance to involve decisions of disposition of radars, routing of transmission line, packet formats of the electric control unit, etc., how to develop staffs with installation techniques and to differentiate data packets and coding formats of various vehicles will be a great challenge.
Since vehicle alarm systems effectively reduce an incidence rate of traffic accident, if installation complexity and production costs of the vehicle alarm systems can be further reduced, and the vehicle alarm systems can be effectively applied in the aftermarket, an installation rate of the vehicle alarm systems will be raised, effectively reducing social costs induced by traffic accidents.